• 한국임상수의학회지
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• 제39권2호
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• pp.81-86
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• 2022

A female, 14-year-old, African penguin (Spheniscus demersus) weighing 2.5 kg with the anorexia for one day and 22 months history of bumblefoot was found dead in aquarium. Grossly, severe bumblefoot in the central surface of the right foot, severe enlarged liver and kidneys with orange color were observed. Histopathologically, pinkish amorphous materials were accumulated in liver, spleen, kidney, and stomach. The pinkish materials in the liver, kidney, spleen, and stomach were confirmed as amyloid with typical orange color reactions using Congo red stain under the light microscope and with bright red color expressions using Congo red stain under the fluorescence microscope. Based on the typical gross and histopathologic findings and special staining, this case was confirmed as systemic amyloidosis. A long period time of moderate bumblefoot might be closely associated with the occurrence of systemic amyloidosis in the captive penguin.

• Bulletin of the Korean Chemical Society
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• 제31권5호
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• pp.1128-1134
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• 2010

Nanocarbon supported Fe/$TiO_2$ composite catalysts were prepared using CNTs (carbon nanotubes) and $C_{60}$ (fullerene) as nanocarbon sources by a modified sol-gel method. The Fe/$TiO_2$-nanocarbon composites were characterized by the BET surface area, scanning electron microscope (SEM), Transmission Electron Microscope (TEM), X-ray diffraction (XRD), energy dispersive X-ray (EDX) and UV-vis spectra. In comparison with non-nanocarbon doped Fe/$TiO_2$ composites, the nanocarbon supported Fe/$TiO_2$ composites had higher absorption ability with a larger specific surface area, and showed higher photocatalytic activity during the degradation of methylene blue (MB) under visible light. The reasons for the obvious increase of photocatalytic activity indicated that the photoactivity not only benefits from nanocarbon introduced, but also relates to the cooperative effect of the Fe as a dopant.

• Tribology and Lubricants
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• 제20권2호
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• pp.51-57
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• 2004

Micro/nano adhesion and friction properties of mixed self-assembled monolayer (SAM) with different chain length for MEMS application were experimentally studied. Many kinds of SAM having different spacer chains(C6, C10 and C18) and their mixtures (1:1) were deposited onto Si-wafer, where the deposited SAM resulted in the hydrophobic nature. The adhesion and friction properties between tip and SAM surfaces under nano scale applied load were measured using an atomic force microscope (AFM) and under micro scale applied load were measured using ball-on-flat type micro-tribotester. Surface roughness and water contact angles were measured with SPM (scanning probe microscope) and contact anglemeter. Results showed that water contact angles of mixed SAMs were similar to those of pure SAMs. The morphology of coating surface was roughened as mixing of SAM. Nano adhesion and nano friction decreased as increasing of the spacer chain length and mixing of SAM. Micro friction was decreased as increasing of the spacer chain length, but micro friction of mixed SAM showed the value between pure SAMs. Nano adhesion and friction mechanism of mixed SAM was proposed in a view of stiffness of spacer chain modified chemically and topographically.

• Preventive Nutrition and Food Science
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• 제11권1호
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• pp.61-66
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• 2006

The objective of this study was to compare the color and microstructure of powder, redness, brownness, and antioxidative activity in extruded ginseng, white ginseng and red ginseng extracts. The colors of extruded dry ginseng powder (moisture content 30%, barrel temperature $110^{\circ}C$, and screw speed 200 rpm) were similar to those of red ginseng. Intact cell wall structure was examined in dried root ginseng at $70^{\circ}C$ (A), white ginseng with skin (D), white ginseng without skin (E), and red ginseng (F) under a scanning electron microscope. The cell wall was not detected in samples B and C (dry ginsengs extruded with 25% and 30% moisture contents, respectively). Intact starch granules were detected in samples A, D, and E under a scanning electron microscope. Melted starch granules were detected in samples B, C, and F. Colors (L, a, b) of 50% EtOH extracts were similar in samples C and F. Browniness and redness of extracts were high in extruded dry ginseng and red ginseng extracts. Extruded dry ginseng (B) showed higher electron donation ability and phenolic content than the other samples.

• 대한치과보철학회지
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• 제40권4호
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• pp.323-334
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• 2002

The purpose of this study is to investigate which current densities and etching times will result in an optimal etching depth and surface roughness when an Ni-Cr-Be alloy is etched with 30% perchloric acid($HClO_4$). For this study, observations were made by means of an optical three-dimensional surface roughness measuring machine and a scanning electron microscope. The etchings took place under the following conditions using current densities of $300mA/cm^2\;450mA/cm^2,\;600mA/cm^2$ and $750mA/cm^2$, and using etching time of three, five, six, seven and nine minutes. Under the conditions, the experiments reached the following conclusions. 1. When the current density is above $450mA/cm^2$ and the etching time is longer than five minutes, the etching depth increased as the current density and etching time increased. And the surface roughness was significantly influenced by the interaction of the current density and etching time. 2. Under the etching conditions of $600mA/cm^2$ and five minutes, the optimal etching depth for a resin cement space and the highest surface roughness for mechanical retention were obtained. The etching depth and surface roughness were $32.86{\mu}m$ and $7.90{\mu}m$, respectively. 3. Observations under the scanning electron microscope showed that both the corrosion at the grain boundary and the corrosion within the grain occurred on the etched surface. It was also observed that the corrosion at the grain boundary became more severe as the current density and etching time increased. In addition. at higher current densities and longer etching times general corrosion appeared.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1888-1891
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• 2003

In this paper, we proposed a new method to control the length of carbon nano tube in the single CNT probe. A single CNT probe was composed of a tungsten tip made by the electrochemical etching and carbon nano tube which was grown by CVD and prepared through the sonication. The two components were attached with the carbon tape. Since the length of CNT can not be controlled during the manufacturing, the post process is needed to shorten the CNT. In this paper, we proposed the method of electrochemical process. The process was done under the optical microscope and the results were checked by SEM. The diameter of the carbon nano tube used in this paper was about 130nm because the above process had to be done with the optical microscope. Using the method proposed in this paper, we can control the length of the nano tube tip.

• Journal of Welding and Joining
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• 제23권2호
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• pp.59-65
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• 2005

A leaky surface acoustic wave (LSAW) velocity was measured using a scanning acoustic microscope on the ceramic/metal interface in order to investigate material properties. The inverse Fourier transform (IFFT) of the V(z) curve contains the reflectance function of a liquid-specimen interface. So, the longitudinal, transverse, and Rayleigh wave velocities for each layer are obtained by the inversion of the V(z) curve at the same time. This paper contains mainly the experimental procedure for measurements of the LSAW velocity, and the results obtained for the velocity variation of individual layer after the thermal shock. It is shown that this method is useful in measuring the material properties under external stress.

• 한국식물병리학회지
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• 제14권5호
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• pp.467-472
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• 1998

Gray mold rot of perilla was epidemic at Kangdong, Pusan and Miryang, Kyungnam in 1997 and 1998. The incidence of this disease ranged form 21.3 to 68.1% at Kangdong area. Leaf necrosis initially appeared on the edge of the infected leaves, and it was developed to the center of the leaves forming typical V-shaped brown necrotic lesions. Under high moisture condition, abundant mycelia of the pathogen was formed on the surface of the lesions. Infected stems became slender and were completely blighted up to the top of the plant. Two isolates, LVF12 and SD7, were isolated from diseased lesions showing typical symptoms, and the pathogenicity was tested using mycelial disks and conidial suspension inoculation. The developed symptoms were same as the naturally produced ones. These two pathogenic fungi were identified as Botrytis cinerea based on the morphological characteristics using a microscope and a scanning electron microscope, and cultural characteristics. This is the first report of gray mold or perilla in Korea.

• Applied Microscopy
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• 제13권1호
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• pp.41-47
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• 1983

A Scanning electron microscope which can obtain additional information not readily available with either the light or transmission electron microscope was used to study the mast cell shape and its granules in normal mammal tissue(rat mesentery, stomach and mouse stomach) by fretting cut using liquid nitrogen. The results showed that rat mesentery and mouse stomach mast cell surfaces had no ridges and microvilli, but revealed several microvilli projecting into the surrounding connective tissue in the rat stomach mast cell. The shape of the mast cell varied from discoid(in the rat mesenteric mast cell) to ellipsoid (rat and mouse stomach), ranging from 7.5 to $10{\mu}m$ in diameter. The shape of the nucleus was ellipsoid and nucleic membrane was adherent to the outer surface of the granules. The granules, approximately 0.2 to $0.9{\mu}m$ in diameter, were various shapes. Frequently, rounded protrusions of cytoplasmic granules could be discerned under the cell membrane. Many small granules were seen in the cytoplasm.

• Journal of Plant Biology
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• 제27권2호
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• pp.81-94
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• 1984

Anatomical features and cell dimensions of the secondary xylem in the stem of the korean Lauraceas including 6 genera and 12 species were investigated under a light microscope and scanning electron microscope. Key to identification among genera or species was made from the anatomical features and systematic correlation investigated. The stem woods of Lauraceae exhibit the following characters: (1) quite evenly distributed pores (diffuse-porous wood) (2) perforation plates simple or occasionally scalariform in the latewood vessels (3) almostly 2-seriate and heterocellular rays (4) abundant paratracheal-vasicentric parenchyma (5) oil cells. Especially, the appearance of simple perforation plates suggest the Lauraceae to be more or less advanced. It is considered that the series of specialization in the Lauraceae from the perforation plates and the height of rays is as LinderalongrightarrowNeolitsealongrightarrow(Machilus, Litsea, Iozoste)longrightarrowCinnamomum, and Lindera sericea is the most pribitive in the Lauraceae.